Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems.
Generally, a wireless multiple-access communications system may include a number of base stations, each simultaneously supporting communication for multiple user equipments (UEs such as mobile devices). Base stations may communicate with UEs on downlink channels (e.g., for transmission from a base station to a UE) and uplink channels (e.g., for transmission from a UE to a base station). Each base station has a coverage range, which may be referred to as the coverage area of the cell. As a UE moves from one coverage area of the cell to the next, it may become necessary for the serving base station to handover communication of the UE to a target base station. Handover allows for a UE to remain connected to a base station providing satisfactory downlink channel conditions.
In a conventional wireless network, intra or inter-carrier handover processes of a UE are initiated based solely on the downlink channel measurements (i.e., transmission conditions from the base station to the UE). Therefore, as the downlink channel conditions deteriorate between the serving base station and the UE, a handover process is initiated to transfer the UE control from the serving base station to a target base station that may provide improved downlink channel conditions.
However, uplink performance of a UE may not always correspond to its downlink performance. For example, based on user's mobility from one cell to the next, the downlink channel conditions of the UE may improve, while the uplink channel conditions of the UE may remain unaffected. As a result, while the target base station may provide improved downlink channel conditions for the UE following a handover, the uplink channel conditions at the target cell may not be ideal. Therefore, triggering a handover based solely on the downlink channel measurements may not be optimal for a user engaged in an uplink data communication.